Writing in Chinese is very difficult to master because there is no such thing as an alphabet in the language. Instead, it employs a system of 20,000 characters. To make learning them easier, they can be translated into Roman characters using pinyin.
The writing system itself is also one of the oldest in the world. Chinese characters were found on animal bones in 1600 BC. The Latin alphabet wasn’t invented until 1000BC.

Watch Your Tone

Chinese is a tonal language so the tone used while speaking makes the words mean different things. Mixing up the rising or falling pitch of words will make something like “I want to ask you” into “I want to kiss you.” So it’s important to get those inflections down in order to avoid making an embarrassing mistake.

Grammar Tenses

Chinese does not have any grammatical tenses in it. But it does have other complexities that aren’t present in other European languages, such as a system of suffixes and the relevancy of occurrences.